The present invention relates to a piston head assembly and more particularly to a piston head with a piston ring of polytetrafluorethylene fiber.
JP-B2 4-81074 published on Dec. 22, 1922 discloses a piston head with a piston ring of polytetrafluorethylene fiber. According to this prior art, the piston ring has a series of axially spaced projections received in a series of circumferentially spaced grooves with which the piston head is formed. The piston head has a deeper groove and a tapered surface partly defining the deeper groove, while the piston ring is turned toward its axial end to mate with the tapered surface.
An object of the present invention is to provide an improved piston head assembly of the above kind.